Medical leads often include multiple filars that carry electrical signals between electrical circuitry of medical devices and electrodes on a distal end of the medical leads. The filars extend from connectors on a proximal end of the medical leads to the electrodes on the distal end.
During construction of the medical leads, the filars are initially placed within an interior of a lead body. In many cases, the lead body includes a central lumen and the filars are present within the central lumen. The filars within the central lumen may be coiled to offer flexibility and extendibility to the lead. The filars must be brought into physical contact with the electrical connectors and electrodes on the proximal and distal ends of the leads. This is largely a manual task where a technician must cut a slit in the lead body, select a filar, and pull the filar through the slit. The filar is then physically attached to the electrode that is placed over the lead body nearby the slit.
Selecting the filar and pulling it through the slit can be a burdensome task, especially where the filars are coiled within the lead body. Where the filars are coiled, the technician must first unwind the filars over a certain length so that the filars can be individually grasped to pull through the appropriate slit in the lead body. The more burdensome the task of assembling the medical leads, the more costly the process in terms of the amount of time spent per lead.
Once a medical lead is constructed, it is then used in practice by being inserted into a medical device by a clinician during the installation of the medical device for a patient. When installing the medical lead, the clinician grasps the proximal end and inserts the proximal end into a port of the medical device. The stiffness of the proximal end of the lead affects the amount of insertion force that may be supplied. If the proximal end is not adequately stiff, the clinician may have trouble properly inserted the lead. However, if the whole lead body is stiff, then routing the lead body to the stimulation site within the patient becomes difficult and the lead is more susceptible to movement and damage due to movements of the patient.